Method of making filament

ABSTRACT

A method of insuring the spontaneous release of a filament formed by contacting the surface of a molten material with the circumferential edge of a rotating heat-extracting member by applying a film of cooling liquid to the external surface of the circumferential edge.

PATENTEBUBI 22 m4 3.843762 SHED 1 0F 2 Fig. I

States Patent 11 1 1111 3,843,762 Sleigh 1 Oct. 22, 1974 METHOD OFMAKING FILAMENT 7,315 3/1910 (11.3111 1311111111 .1 164/87 0 45-5243 27) 1 1 .t 2 3 [76] Inventor: Gordon Sleigh, 95 Meriton Rd., H9 Jlpm 164/8 Handforth, Wilmslow, England Primary Examiner-R. Spencer Annear [22]May 1973 Attorney, Agent, or Firm-Stephen L. Peterson [2]] Appl. No.:365,083

52 11.5.0 264/213, 264/8, 264/215, 7 ABSTRACT 164/87 [64/283 M A methodof insuring the spontaneous release of a fila- [51] Int. Cl. B22cl13/00, DOld 5/00 58 M fs h 164/87 276 283 R 283 ment formed bycontacting the surface of a molten 1 0 264i; 212 i material with thecircumferential edge of a rotating heat-extracting member by applying afilm of cooling References Cited to the external surface of thecircumferential FOREIGN PATENTS OR APPLICATIONS 1961.957 9/1970Germany 1. 164/278 6 Claims, 3 Drawing Figures METHOD OF MAKING FILAMENTBACKGROUND OF INVENTION The present invention relates to the art ofmaking elongated filamentary articles by rotating a heatextractingmember in contact with a source of molten material and solidifying aportion of the molten material as a filamentary product on the surfaceof the rotat' ing member where it spontaneously releases and issubsequently collected.

Prior art methods of producing filamentary articles conventionallycomprise casting and repeated mechanical deformation techniques disposedto sequentially reduce the cross-sectional area of the elongated member.The complexity and cost of such operations have created along standingdemand for amethod of forming filamentary material directly from thematerial in the molten state.

One proposed method involves the use of a rotating heat-extractingmember in contact with the surface of a source of molten material. Themember is shaped so as to limit the area introduced to the moltenmaterial and thereby solidify a filamentary article adherent thereto.The adherent filament is subsequently released from the forming memberand is then collected. The spontaneous release of the previouslyadherent filamentary article is most important since the speed ofoperation and the size of the filament preclude the use of any scrapingmeans to insure filament release. Furthermore, where the edge of theheat-extracting member is in contact with molten materials having highmelting points (e.g., over 1,000 C) the resultant erosion and oxidationof the forming edge inhibits spontaneous release of the filament. Whilethe use of internal circulation of cooling fluids within the member canreduce this effect the present invention substantially reduces theoxidation and erosion of the circumferential edge by applying anexternal film of cooling liquid to the edge.

SUMMARY OF THE INVENTION The present invention comprises the applicationof a liquid film to the external edge of a disk-like heatextractingmember forming filamentary material by contacting the surface of asupply of molten material and solidifying a portion of that material onthe circumferential edge of the heat-extracting member. Prior arttechniques are hindered by the erosion or oxidation of this edge whicheffects the spontaneous release of the filaments formed thereon. Inimproving the cooling of the edge the present invention insuresspontaneous release of the filament by preventing excessive heatbuildupat the edge and thereby preventing oxidation or erosion of thecircumferential edge of the heatextracting member.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross sectionshowing one embodiment of the present invention in side view.

FIG. 2 illustrates the embodiment of FIG. 1 rotated 90.

FIG. 3 is a cross-sectional view of the heatextracting member showingthe operation of the present invention including the use of the internalcoolant as the supply for the external cooling film.

2 DETAILED DESCRIPTION OF HE INVENTION The present invention is animprovement of a filament forming method operable with materials that,in

their molten state, have properties similar to those of I molten metals.Specifically the moltenmaterials operable with thepresent'invention musthave (at a temperature within 25 percent of their equilibrium meltingpoint in degrees Kelvin): a surface tension in the range of from to2,500 dynes/cm, a viscosity in the range of from l0 to l poise and areasonably discrete melting point (Le, a discontinuous viscosity versustemperature curve). Such molten materials are contacted on their surfaceby a rotating heat-extracting member generally in the manner shown inFIG. 1. I

The molten material 10 is contacted at thesurface 11 by thecircumferential edge 32 of the rotating heatextracting member 30. In theembodimentshown the circumferential edge 32 is V-shaped with the apex ofthe V in contact with the melt surface 11. Byremoving heat from themolten material 10 a filamentary product is formed on the edge 32. Therotation of the member causes the edge 32 to be continuously advancedthrough the melt surface ll'as-well as promoting the spontaneous releaseof the filament 20 from the edge at the release point 35. y

The improvement of the process resides in the application of a coolingfilmto the circumferential edge of the heat-extracting memberand themeans shown in FIGS. 1 and 2 include a supporting member 40 containing aporous member 41 exposed to the application of a cooling liquid shownhere simply as a tube 42 and a flow regulating valve 43; The porousmember 41 isin contact with the circumferential edge 32 of the rotatingmember 30.

The embodiment shown in FIGS. 1 and 2 is in no way the only operablemeans of applying the cooling film. Other means would include the use ofliquid sprays or aerosols, the direct application of the liquid to theedge etc. The inventive concept of the present invention is not themeans used to apply the cooling film and one having ordinary skill inthe art can readily devise means of dispensing and applying liquid tothe edge using means not specifically described herein.

FIG. 3 illustrates an embodiment of the invention where the source ofthe cooling film is the liquid coolant circulating within theheat-extracting member. The member 30 is formed so as to allow a liquidcoolant 50 to circulate internally so as to increase the capacity of themember 30 to remove heat from the molten material 10. The member 30 inthis embodiment includes a porous section 38 that allows a portion ofthe internal coolant 50 to pass from the internal cavity onto thesurface of the member 30 in the form of a cooling film. Furthermore, ifthe porosity of member were controlled to yield an appropriate flow rateof coolant to the surface the entire heat-extracting member may beporous.

The centrifugal force generated by the rotation of the heat-extractingmember induces the flow of the film toward the circumferential edge 32thereby placing the cooling film at the most critical locationirrespective of the means used to place the film on the external surfaceof member 30. In this manner the edge 32 of the heatextracting member isfurther cooled and oxidation and erosion at that location aresignificantly inhibited. With the condition of the edge stabilized bythe inhibition of oxidation and erosion the spontaneous release of thefilament is insured.

The present invention may be used solely or in conjunction with intemaldisk cooling and such a combination has been used successfully inpreventing oxidation or erosion of a metal disk used to producecontinuous filament from a source of molten steel. While continuousfilament is specifically disclosed and illustrated in the figures thepresent invention is also applicable to a heat-extracting member havingindentations on its circumferential edge of a depth greater than thediameter of the filament formed disposed to attenuatethe solidifiedfilament into discontinuous filament having a length approximating thedistance between indentations.

FIG. 3 also illustrates the configuration of the preferred embodiment ofthe circumferential edge 32. The member 30 has a thickness indicated asT and it preferably is in the range of from 0.10 to 2.0 inches. Theradius R of the disk preferably is in the range of from 2 to inches andthe radius of curvature r of the edge 32 is preferably in the range offrom 0.0005 to 0.10 inch. The edge 32 is passed through the surface ofthe melt at a linear rate in excess of 3 ft/sec.

The liquid used as the coolant may be water or any liquid that does notchemically attach the molten material or the material comprising thedisk. The coolant should be chemically unreactive with the atmospheresurrounding the process at the operating temperature and preferably benon-flammable.

I claim:

1. In a method of forming filamentary material from a source of moltenmaterial havingproperties in the molten-state substantially similar tomolten metals by rotating the circumferential edge of a disk-likeheatextracting member in contact with the surface of said moltenmaterial while limiting the area'of contact of said edge with saidsurface, solidifying said material in solid filamentary form on saidedge and spontaneously releasing the filament from said edge theimprovement comprising:

applying a film of cooling liquid externally to said edge at a pointbetween the location of spontaneous filament release and the point wheresaid edge enters the surface of said molten material. I 2. The method ofclaim 1 where said disk-like heatextracting member is internally cooledby circulation of liquid therethrough with a portion of the internalcooling liquid passing through said member so as to form an externalfilm of cooling liquid.

attenuate the filament into discontinuous lengths.

1. In a method of forming filamentary material from a source of moltenmaterial having properties in the molten state substantially similar tomolten metals by rotating the circumferential edge of a disk-likeheat-extracting member in contact with the surface of said moltenmaterial while limiting the area of contact of said edge with saidsurface, solidifying said material in solid filamentary form on saidedge and spontaneously releasing the filament from said edge theimprovement comprising: applying a film of cooling liquid externally tosaid edge at a point between the location of spontaneous filamentrelease and the point where said edge enters the surface of said moltenmaterial.
 2. The method of claim 1 where said disk-like heat-extractingmember is internally cooled by circulation of liquid therethrough with aportion of the internal cooling liquid passing through said member so asto form an external film of cooling liquid.
 3. The method of claim 1where said film is produced by directly applying said cooling liquid tosaid circumferential edge.
 4. The method of claim 3 where said coolingliquid is applied to a porous medium in contact with saidcircumferential edge.
 5. The method of claim 3 where said cooling liquidis applied to said circumferential edge in the form of a liquid spray.6. The method of claim 1 including the step of providing notches on saidcircumferential edge disposed to attenuate the filament intodiscontinuous lengths.